Ammonium nitrate is a hygroscopic white solid, which means that it will absorb moisture from the atmosphere. It is an oxidising agent that gives off nitrogen oxides, mainly nitrous oxide, when heated. It is normally made in the form of small white balls, about two millimetres in diameter.
Fritz Haber invented the process used all over the world to make ammonia from nitrogen and hydrogen. He also devised gases for the World War effort on Germany’s behalf, such as chlorine, phosgene and mustard gas.
How is nitric acid manufactured?
Nitric acid is manufactured by reacting ammonia with oxygen from the air, in the presence of a platinum catalyst, to form nitrogen oxides that are then absorbed in water.
Commercial grade nitric acid is typically 62 per cent w/w. It is a transparent, colourless to yellowish liquid, which readily fumes to produce, a suffocating effect if inhaled. It is a strong oxidising acid, is very corrosive and will dissolve most metals.
Most nitric acid is used in making ammonium nitrate but it is also used in the manufacture of organic and inorganic nitrates. Direct applications include photoengraving and metal pickling.
The following are Reactions of Nitric Acid
Cuprous Oxide, Cu2O reacts with dilute Nitric Acid, HNO3, in the cold to form a solution of Cupric Nitrate, Cu (NO3) 2, and Copper, Cu.
Cu2O + 2 HNO3 ==> Cu (NO3) 2 + Cu + H2O
Cuprous Oxide, Cu2O reacts with concentrated Nitric Acid, HNO3, or with dilute Nitric Acid, HNO3, on heating, when the Cuprous Oxide, Cu2O dissolves with evolution of Nitric Oxide, NO.
3Cu2O + 14HNO3 ==> 6Cu(NO3)2 + 2NO + 7H2O
Dinitrogen Pent oxide, N2O5, is best prepared by dehydrating concentrated Nitric Acid, HNO3, by Phosphorus Pent oxide, P2O5.
2 HNO3 + P2O5 ==> N2O5 + 2 HPO3
Nitric Oxide, NO is prepared be the action of Copper, Cu, or Mercury, Hg, on dilute Nitric Acid, HNO3, and was called Nitrous Air.
3 Cu + 8 HNO3 ==> 3 Cu(NO3)2 + 2 NO + 4 H2O
Nitrogen Dioxide, NO2, is a mixed acid anhydride and reacts with water to give a mixture of nitrous and nitric acids.
2 NO2 + H2 ==> HNO2 + HNO3
If the solution is heated the nitrous acid decomposes to give nitric acid and nitric oxide.
3 HNO2 ==> HNO3 + 2 NO + H2O
The mixture of gases is cooled and nitrogen monoxide reacts with further oxygen in the air to produce nitrogen dioxide:
Nitric acid is used in the manufacture of fertilisers and explosives.
